Along with the development of the information technology, higher demands, e.g., high resolution, large brightness value, small response time and low power consumption, have been set on a display product. These demands may be met through a TFT having an active layer made of a transparent metal oxide. Hence, the application of a transparent metallic oxide material to a next-generation liquid crystal display (LCD) and an organic light-emitting diode (OLED) display device has attracted more and more attentions.
In the related art, in the case of manufacturing an oxide TFT, an active layer of the oxide TFT is made of a metal oxide, so its stability is susceptible to oxygen, hydrogen and water in a wet-etching environment. Currently, in most of the time, a signal line and a source/drain electrode are each made of a composite material consisting of copper and its barrier metal, and an etchant includes hydrogen peroxide as a principal component. In this way, it is able to prevent the active layer made of the metal oxide from being etched.